Severe neonatal anemia from fetomaternal hemorrhage: report from a multihospital health-care system

OBJECTIVE: The incidence of fetomaternal hemorrhage that is severe enough to cause neonatal anemia is not known. Owing to its relative rarity, much of the literature describing this condition is in the form of case reports and small case series. We performed a large, muiticentered, sequential, case series to determine the incidence, antecedents and outcomes. STUDY DESIGN: From the multicentered databases of Intermountain Healthcare, we obtained records of all neonates with hematocrit (Hct) <30% or hemoglobin (Hgb) <10 g dl(-1) on the day of birth, who had Kleihauer-Betke staining or flow cytometric evidence of fetomaternal hemorrhage. RESULT: Among 219 853 live births, 24 had anemia with evidence of fetomaternal hemorrhage (incidence estimate, 1 per 9160 live births). The initial Hgb ranged from 1.4 to 10.2 g dl(-1) (Hct 29.8%). The initial Hgb was <7gdl(-1) in 18 (67%), <5gdl(-1) in 12 (50%) and was <3 gdl(-1) in 7 (29%). All 7 mothers in whom neonatal Hgb was <3 gdl(-1) had reported absent fetal movement, as did 13 of 18 mothers when the initial Hgb was <7 gdl(-1). Outcomes were poorer in those with the lowest initial Hgb; in the two lowest, one died on day 1, and the other developed a grade 4 intraventricular hemorrhage (IVH). The adverse outcomes of death, IVH, periventricular leukomalacia, bronchopulmonary dysplasia or hypoxic-ischemic encephalopathy were common; occurring in 71% (17 of the 24), including all with an initial Hgb <5 gdl(-1) and all born at p35 weeks of gestation. CONCLUSION: Fetomaternal hemorrhage is a rare but sometimes devastating condition. Those with fetomaternal hemorrhage and an initial Hgb of <5 gdl(-1) are expected to need resuscitation at birth, to receive emergent transfusion support and to be at risk for death and major morbidities. Antenatal suspicion of this diagnosis should occur when absent fetal movement is reported. Improvements in rapid diagnosis are needed to prepare first responders and transfusion services.